MANAGING BACTERIAL DISEASES

Accurate diagnosis is the first step in a control strategy.

- Raylene Nickel

When hail, high winds, or heavy rains damage crops, even minor bruising of corn leaves can give bacterial diseases an opportunity to get started. Once a corn crop is infected, the disease organism can overwinter in crop residue, giving way to a repetitive cycle of disease.

With bacterial diseases in corn, in-season management options to control the pathogen are limited. But accurate diagnosis can kick-start longer-term management changes and prevent misapplying fungicides, which are not effective in controlling corn bacterial diseases.

“In Nebraska, the most common bacterial diseases of corn are bacterial leaf streak and Goss’s bacterial wilt and blight,” says University of Nebraska Extension plant pathologist Tamra Jackson-Ziems. “In the rest of the country, bacterial leaf streak is not as common as it is in the western Corn Belt. It was first reported in Nebraska in 2016, which was the first time the disease had been reported in the United States. Since then, it has been confirmed in at least eight more states.”

With bacterial leaf streak, yield loss is hard to confirm, Jackson-Ziems says, partly because corn hybrids differ in their reactions to the disease. Yield losses resulting from Goss’s bacterial wilt and blight have been easier to pin down because the disease has a longer track record of infecting crops.